The core will provide standardized surgical procedures, behavioral, histological and neurochemical analysis to all projects. Specifically, the core will provide rats with 6-hydroxydopamine-induced lesions of the nigrostriatal pathway, with continuous L-DOPA delivery by osmotic minipumps, with implanted GABA-producing cells and with implanted deep brain stimulators of the subthalamic nucleus, and their respective controls. The core will provide behavioral analysis to assess motor behavior in untreated and treated rats with nigrostriatal lesions and their controls. The core will provide histological analysis of lesions, cannula and electrode placement, transplant location and size, and of morphological integrity of the subthalamic nucleus. The core will provide neurochemical analysis of dopamine depletion. In addition, the core will collect and perform neuropathological examinations of post-mortem human brains of patients with Parkinson's disease and controls. This tissue will be used in project 1 and will be made available to other investigators outside the Center.